Análise genética de características ponderais e reprodutivas de fêmeas bovinas Tabapuã / Genetics analysis of growth and reproduction traits in a herd of Tabapuã females

RESUMO

Foram estudadas 1251 informações referentes aos pesos às idades-padrão de 205 (P205), 365 (P365) e 550 (P550) dias e idade ao primeiro parto (IPP) e primeiro intervalo de partos (IEP1) de fêmeas bovinas da raça Tabapuã. As médias, desvios-padrão e coeficientes de variação foram respectivamente P205 173,9kg, 16,0kg e 9,2%; P365 225,7kg, 28,7kg e 12,7%; P550 277,0kg, 36,7kg e 13,3%; IPP 1125,5 dias, 106,6 dias e 9,5% e IEP1 522,2 dias, 106,2 dias e 20,7%. As estimativas de componentes de (co)variância e de parâmetros genéticos foram obtidas pelo método de máxima verossimilhança restrita, utilizando-se o software MTDFREML. Para cada característica as estimativas de herdabilidade foram de 0,16, 0,25, 0,29, 0,03 e 0,01, na mesma ordem de citação acima. As correlações genéticas entre as características ponderais e reprodutivas foram -0,67 (P205×IPP); -0,07 (P365×IPP); -0,41 (P550×IPP); 0,19 (P205×IEP1); 0,79 (P365×IEP1) e 0,64 (P550×IEP1).(AU)

ABSTRACT

Records on weaning, yearling and 550-day weights, age at first calving and first calving interval from 1251 Tabapuã females, born between 1987 and 1999, were used to estimate variance components and genetic parameters. Statistical analyses were performed and components of (co)variance and genetic parameters were estimated by the derivative-free algorithm based on an animal model. The heritability estimates for weaning, 365 and 550 day weights, age at first calving and first calving interval were 0.16, 0.25, 0.29, 0.03 and 0.01, respectively. The genetic correlations between weight at those ages and age at first calving were -0,67; -0,07; -0,41, respectively, and between weights (at weaning, 365 and 550 days) and first calving interval were 0.19, 0.79 and 0.54, respectively. These results showed a genetic antagonism between weight at different ages with first calving interval, but not with age at first calving.